Various proposals have been suggested for forming a thin plastic shell product by apparatus and methods which utilize a heated mold and a casting system for distributing thermoplastic material on the mold. When the mold is heated the cast material is melted and fused to form a shell conforming to the shape of the mold.
U.S. Pat. No. 4,610,620 discloses apparatus for molding plural colored plastic hollow shells by a process in which a decorative pinstripe is formed as an integrally bonded joint between first and second segments of th shell. The joint between the shell components is used to replace a mechanical connection between the segments and to define a color contrasting decorative feature in the finished part. The decorative feature is limited to a joint line application and is not formed in situ of a background base layer bonded thereto.
U.S. Pat. No. 4,562,025 discloses a mold method and apparatus for multicolored plastic shells which include first and second colored segments on the cast shell product directly bonded to one another. Again, there are no decorative features formed in situ on the cast shell components of the product.
U.S. Pat. No. 4,562,032 discloses a method for forming grain coverings on reaction injection molded articles. Such coverings are found on instrument panels and can include embedded stitch features around the periphery of the article to simulate stitched material.
Other proposals have been suggested for providing decorative features on plastic articles, including attachment of the decorative feature by separate connectors or by the use of adhesives.